Epoxy resin compositions, prepreg, and fiber-reinforced composite materials

Abstract

This invention relates to an epoxy resin composition for fiber-reinforced composite materials, which contains the following constituent components (A), (B), and (C). Component (A) contains at least one poly-naphthalene-based epoxy resin, component (B) contains at least one alicyclic epoxy resin and/or a divinylarene diepoxide resin, and component (C) contains at least one amine curing agent. This epoxy resin composition, containing a specific combination of particular types of epoxy resin and curatives, provides high heat resistance and high flexural modulus under extreme environmental conditions. More particularly, a cured resin prepared by the epoxy resin composition offers well balanced mechanical properties that are suitable for preparing fiber-reinforced composite materials useful in aircraft components, spacecraft components, automobile components, artificial satellites components, industrial components, and the like.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is the U.S. National Phase application of PCT / IB2019 / 001051, filed Sep. 20, 2019, which claims priority to U.S. Provisional Application No. 62 / 734,541, filed Sep. 21, 2018, and to U.S. Provisional Application No. 62 / 897,633, filed Sep. 9, 2019, the disclosures of each of these applications being incorporated herein by reference in their entireties for all purposes.FIELD OF THE INVENTION[0002]The present application provides an epoxy resin composition for fiber-reinforced composite materials that are well-suited for aerospace applications, sports applications, and general industrial applications.BACKGROUND OF THE INVENTION[0003]Fiber-reinforced composite (FRC) materials comprising a reinforced fiber and a matrix resin have excellent mechanical properties such as strength and rigidity while being lightweight, and therefore are widely used as aircraft members, spacecraft members, automobile members, railway car members, ship members, sp...

AI Technical Summary

Benefits of technology

[0022]Therefore, the present invention seeks to provide an epoxy resin composition that has, when cured, well balanced properties between resin modulus, flexural strength, and heat resistance. Another advantage over epoxy resin compositions described in the prior art is that the fiber-reinforced composite material prepared using the inventive epoxy resin composition has excellent performance under hot / wet conditions tested above 120° C. It has been surprisingly found that even a small amount of alicyclic epoxy resin and / or divinylarene dioxide epoxy resin or other liquid epoxy resin having a viscosity of less than 1 Pa·s at 25° C. in combination with a poly-naphthalene-based epoxy resin having at least two naphthalene moieties per molecule and at least two glycidyl ether groups per molecule and an amine curing agent (especially an aromatic polyamine curing agent) provides an epoxy resin composition that, when cured, exhibits excellent heat resistance, flexural modulus, flexural strength, and low water absorption. In some embodiments, a catalyst and glycidyl amine epoxy resin and / or glycidyl ether epoxy resin may be used to accelerate the cure of the epoxy resin composition and to improve the handleability.

[0023]The present invention also provides a prepreg comprising carbon fibers impregnated with an epoxy resin composition in accordance with any of the above-mentioned embodiments as well as a carbon fiber-reinforced composite material obtained by curing such a prepreg. Further embodiments of the invention provide a carbon fiber-reinforced composite material comprising a cured resin product obtained by curing a mixture comprised of an epoxy resin composition in accordance with any of the above-mentioned embodiments and carbon fibers. This epoxy resin composition is useful in the molding of fiber-reinforced composite materials. More particularly, the present invention makes it possible to provide an epoxy resin composition for a fiber-reinforced composite material where the cured material obtained by heating has a high-level heat resistance and strength properties. In the field of this invention, a material having a high level of heat resistance is defined as a material having a hot / wet glass transition temperature of above 200° C. and good mechanical properties at or close to a temperature of 150° C.

Problems solved by technology

However, this type of epoxy resin composite has large amounts of water absorption, resulting in the hot / wet properties being impaired, particularly when tested above a temperature of 120° C.

However, the fiber-reinforced composite performance of these epoxy resin compositions under hot / wet conditions tested above 120° C. showed a huge reduction in mechanical properties.

The use of solid type epoxy resin containing more than two epoxy functional groups per molecule provides a high level of heat resistance, but such formulations have a higher viscosity and are difficult to process.

However, these epoxy resin compositions include a large amount of liquid epoxy resin resulting in a huge reduction in hot / wet performance tested above 120° C. Additionally, the forming of rigid crosslinking structures adversely affects the flexural elongation, which is unfavorable to the fracture toughness.

However, the fiber-reinforced composite performance of these epoxy resin compositions under hot / wet conditions tested above 120° C. also showed a huge reduction in mechanical properties.

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